| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate processing apparatus maintaining the etching characteristics of a phosphoric acid solution for a long period of time. SOLUTION: An additive containing a hexafluorosilicic acid solution (H<SB>2</SB>SiF<SB>6</SB>+H<SB>2</SB>O) is sequentially charged into a phosphoric acid solution pooled in an immersion bath 10 from an additive input mechanism 30. Also, a trap agent containing a fluoroboric acid solution (HBF<SB>4</SB>+H<SB>2</SB>O) is charged into the phosphoric acid solution from a trap agent input mechanism 40. F- which accelerates etching of a silicon nitride film is added as appropriate by sequentially charging the additive and siloxane which increases by the sequential input is etched with hydrofluoric acid generated by decomposition of the fluoroboric acid, to thereby suppress a significant increase in the concentration of siloxane. This makes it possible to maintain respective initial etching rates of the silicon nitride film and a silicon oxide film. COPYRIGHT: (C)2009,JPO&INPIT
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